With increasing beam energy, i.e.  above 2 G\(e\) V, Dalitz decays of the \(\eta \) , higher mass baryon resonances and the two-body decays of vector mesons start to contribute to the invariant masses above the \(\pi ^0\)  mass [1]}, [2]}, [3]}.
The contribution of baryon resonances is particularly interesting because it is known that \(\rho \)  mesons couple to several \(N^*\)  and \(\Delta ^*\)  resonances [4]}.
Calculations based on resonance models describe the \(\rho \)  meson production as a two-step process with the excitation of baryon resonance which subsequently decays into a \(\rho \)  meson.
The short-lived vector meson than further decays into a pair of leptons (\(\mathrm {e}^+\mathrm {e}^-\)  or \(\mu ^+\mu ^-\) ).
Such a picture is equivalent to strict VDM where the resonance-virtual photon coupling is saturated by the \(\rho \) .
However, as discussed in Sec. REF , there is an alternative and more consistent approach to describe such a production via a Dalitz decay of a baryonic resonance, which coherently adds intermediate meson states.
